How the UK recycles millions of dirty old disposable coffee cups

Sharks and wolves share 'ecology of fear'

Ecologists studying how wolves and sharks affect their respective ecosystems have concluded that both predators play a similar role, despite existing in very different environments. Both animals cause a ripple effect, referred to as an "ecology of fear", which gives them a far greater environmental significance than they would otherwise occupy.

The researchers compared studies on wolf and elk interaction in Yellowstone in the US with independent studies on how tiger sharks interact with large marine animals called dugongs off the coast of Australia. Elk were found to alter their behaviour due to the perceived threat of wolves -- dedicating energy to maintaining a constant vigilance and keeping open avenues of escape. As a direct result, the elk graze in less sensitive habitats, meaning that certain threatened shrubs and trees are recovering, along with smaller animals like beavers.

Very similar observations have been made with sharks. When there are large amounts of sharks present in an area, dugongs tend to avoid shallower water where they're more vulnerable, allowing meadows of seagrass in those areas to thrive, along with other plants and marine life that depend on them.

Advertisement

The study, which was undertaken by researchers at Oregon State University and the University of Washington, was published in

Frontiers in Ecology and the Environment. The lead author was William Ripple, who said: "For too long we've looked at ecosystem functions on land and in the oceans as if they were completely separate. We're now finding that there are many more similarities between marine and terrestrial ecosystems than we've realized."

The conclusion? Ecologists should talk to each other more.

Researchers studying terrestrial and marine ecosystems could have far more in common than they realise.